A number of portable workbenches are known. Perhaps one of the most well known portable workbenches is that manufactured by Black and Decker, Inc. under the Workmate.RTM. trademark. While such known workbenches are suitable for their intended purposes, they have certain shortcomings that are addressed by the workbench of the invention.
A simple planing beam has been used by oriental craftsmen for centuries. This device incorporates a triangular support at one end thereof, and allows the workpiece to rest on the floor or ground at the other end thereof. Because a three-point support will always conform to the grounding surface, problems of leveling are not present with this form of workbench.
A workbench is intended to provide a working surface for a task. Frequently, this requires that a workpiece be secured to the working surface of a workbench. Although a number of attachment schemes are known, such schemes generally incorporate fixed attachment points, and only allow for attachment of a workpiece to the upper surface of the workbench by a predetermined fixation method, such as clamps or dogs which are provided with the workbench.
U.S. Pat. No. 1,147,522, granted Jul. 20, 1915 to Loomis describes an adjustable workbench wherein one set ground-contacting legs rides on another set of legs which support a cross-piece, allowing the workbench to be adjusted for height and uneven surfaces.
U.S. Pat. No. 4,877,109, granted Oct. 31, 1989 to Welch et al. describes and adjustable sawhorse having a set of fixed, hollow legs and a set of adjustable legs which are received in the hollow legs, and are moveable at fixed increments.
U.S. Pat. No. 5,007,502, granted Apr. 16, 1991 to Shapiro describes a self-leveling saw horse wherein the leg length is fixed and the cross-piece is adjustable to remain parallel to the supporting surface.
A variety of sawhorse brackets are manufactured, including those manufactured by Crawford Products, Inc., of West Hanover, Mass., which brackets receive pre-cut leg elements in receptacles on the lower surface thereof, and wherein, in some models, a gap is present between a portion of a cross-piece support and the cross-piece.